(WTAI-OGUE OF TUILOIUTES. 323 



MICRODISCUS. 



BELLi-MARGiXATus Wal., 1890; lOtli Rep. U. S. Geol. Survey, p. 630, 



pi. 51, fig. 2, 2a-b. Olenclhis zone. 

 coNNExrs Wal., 1887; Am. Jour. Sci., 3d series, vol. 34, p. 194, pi. 1, 



figs. 4, 4 b. Washington Co., N. Y. Taconic. 



coNNEXus Wal., 1890; 10th Rep. U. S. Geol. Survey, p. 631, pi. 80, 



fig. 9, 9 a-b. Olenellus zone. 

 DAwsoxi Hartt, 1868; Acadian Geol., p. 654, fig. 228. St. John, N. 



B. Mr. Hartt originally described this species under the new 



generic name of Dau-sonia, but on Mr. E. Billings' authority the 



species was referred to Microdiscus in the Acadian Geol. Taconic. 



BAWsoxi Whiteaves, 1878; Am. Jour. Sci., 3d. series, vol. 16, p. 225. 



DAWSOXI Wal., 1884; Bull. U. S. Geol. Survey, No. 10, p. 23, pi. 2, 



figs. 3, 3 a. 

 i>AWSoxi Matt., 1855; Trans. Roy. Soc. Canada, vol. 3, p. 75, pi. 7, 



figs. 11 a-c. 



HELEXA Wal., 1889; Proc. Nat. Mus., vol. 12, p. 41. 



HELENA Wal., 1890; 10th Rep. U. S. Geol. Survey, p. 632, pi. 81, figs. 



1, 1 a. Olenellus zone. 

 Agnostus lobatus Hall, 1847; Pal. New York, vol. 1, i). 258, pi. 67, 



figs. 5 a-f. One mile east of Troy, N. Y. Taconic. 



Agnostus lob.\tcs Rogers, 1858; Geol. Survey Pennsj'lvania, vol. 2, 



p. 820, fig. 614 (1-4). 



LOBATUS Ford, 1873; Am. Jour. Sci., 3d series, vol. 6, p. 135 (foot- 



note). 



LOBATUs Wal., 1886; Bull. U. S. Geol. Survey, No. 30, p. 156, pi. 16, 



figs. 1, 1 a, b. Troy, N. Y. 



LOBATus S. & F., 1888; Bull. Mus. Conip. Zool. Harvard Coll., vol. 



16, p. 36, pi. 2, fig. 13. 



r.OBATus Wal., 1890; 10th Rep. U. S. Geol. Survey, p. 632, pi. 81, figs. 



4 a-b. 



MEEKi Ford, 1876; Am. Jour. Sci., 3d series, vol. 11, p. 371. Troj-, 



N. Y. Taconic. 



MEEKI Wal., 1886; Bull. U. S. Geol. Survey, No. 30, p. 155, pi. 16, 



fig. 4. 



MEEKI Wal., 1890; 10th Rep. U. S. Geol. Siirvey, p. 632, pi. 81, fig. 



3. Olenellus zone. 



PARKKRi Wal., 1886; Bull. U. S. Geol. Survey, No. 30, p. 157, pi. 16, 



figs. 2, 2 a. Township of Georgia, Vt. • Taconic. 



PARKERi Wal., 1890; 10th Rep. U. S. Geol. Survey, p. 632, pi. 80, figs. 



7, 7 a. Olenellus zone. 



I'ULCHELLCS (Hartt MS.) Wal., 1884; Bull. U. S. Geol. Survey, No. 10, 



p. 24. RatclifTs Millstream, N. B.; Manuel's Brook, near Con- 

 ception Bay, N. F. Taconic. 



PCNCTATCS Salt., 1864; Quart. Jour. Geol. Soc. London, vol. 20, p. 



237, pi. 13, fig. 11. St. John, N. B. 



